The Structural Materials Beamline at CHESS

MRS Communications · 2025-10-06 · 1 citations

Abstract The Structural Materials Beamline (SMB) is one of two beamlines at the Cornell High Energy Synchrotron Source (CHESS) sponsored by the Air Force Research Laboratory to develop and apply advanced X-ray techniques for mission-oriented materials challenges facing DoD and DoD-serving manufacturers. SMB is especially optimized for in situ and ex situ studies that link material response to processing or service conditions, often combined with development and validation of predictive models. Specialized instrumentation and methods have been developed to characterize the real-time mechanical response of alloys and to map residual stress fields in metallic components through diffraction-based techniques. Graphical abstract

Characterizing Residual Stresses in Additively Manufactured Alloys at the Cornell High Energy Synchrotron Source

Structural Dynamics · 2025-09-01

One of the major challenges in metal additive manufacturing is the development of residual stresses due to the rapid heating and cooling cycles inherent in the process. These stresses can significantly impact the mechanical performance and structural integrity of additively manufactured components. To quantify these stresses, synchrotron X-ray diffraction provides a powerful, non-destructive technique for measuring internal lattice strains, both during fabrication and after heat treatments, to assess different processing pathways. High-energy synchrotrons offer the flux and penetrating power required to probe dense crystalline materials, such as engineering alloys. By mapping the elastic lattice strains within a sample, residual stresses can be calculated, providing critical data for validating complex thermal processing models. These models help accelerate the adoption of additively manufactured parts by enabling the optimization of print parameters and post-processing treatments. Residual stress measurements, particularly in additively manufactured metal components, have been a cornerstone of the Structural Materials Beamline (SMB) program at the Materials Solutions Network at the Cornell High Energy Synchrotron Source (MSN-C). As a defense research facility funded by the Air Force Research Laboratory, MSN-C focuses on transitioning synchrotron-based methods from academic research to practical engineering tools - a challenge endemic to the synchrotron community limiting industrial access to these measurements. The SMB beamline is equipped with both high-energy monochromatic (40–90 keV) and polychromatic (50–200 keV) X-ray capabilities, enabling the measurement of residual elastic lattice strains in component-sized parts using two primary techniques. The first, Angular X-ray Dispersive Diffraction (ADXRD), is a monochromatic technique that utilizes SMB’s recently acquired large-panel, direct X-ray area detector (Dectris Eiger16M CdTe), making it well-suited for thin-walled structures (less than 7 mm). The second, Energy X-ray Dispersive Diffraction (EDXRD), is a polychromatic technique that employs SMB’s 23-element energy dispersive detector system, allowing for deeper penetration—up to 40 mm in steel—making it ideal for larger component parts. This talk will present the current state-of-the-art in residual stress measurements at SMB developed over the last 6 years, and the readiness of these methods for industrial applications. The complex microstructures of additively manufactured parts pose challenges across measurement techniques, leading to effective error bounds that will be discussed. Additionally, this presentation will cover the challenges associated with stress-relaxed lattice parameter determination in additively manufactured parts, particularly those arising from compositional and microstructural complexities, as well as strategies for improving measurement accuracy.

Subsurface microstructure effects on surface resolved slip activity

Journal of the Mechanics and Physics of Solids · 2025-01-04 · 5 citations

Surface—subsurface grain structure relationships

Acta Materialia · 2024-01-08 · 4 citations

Role of microstructure on the development of local orientation gradients in polycrystals

Journal of Materials Research and Technology · 2024-08-31 · 5 citations

In this work, we study the relationship between slip localizations and local orientation gradients in a polycrystalline material. We employ a 3D spatially resolved crystal plasticity-based micromechanics technique that includes explicit intragranular slip band modeling, called SB-FFT (slip band fast Fourier transform). EBSD analysis reveals the development of slip localizations, with a rare few generating relatively large local orientation gradients in the neighboring grain. Our results find that several conditions need to be met simultaneously for large zone of intense orientation gradients to form within a grain and with this, offer an explanation for their scarcity. These conditions entail the localization of slip to a sufficient high intensity in the grain neighbor, the grain experiencing higher stress levels than the average stress of its nearest grain neighborhood, and a crystallographic orientation suitable for activating secondary slip under the stress field produced by the slip localization. Analysis of the 3D orientation distributions as they evolve in strain indicates that orientation gradient zones cause the distribution to become highly skewed, with the extreme tails extending further as strain increases. The numerical simulations with various grain neighborhoods show that this feature is, however, not a sufficient signature for such orientation gradients associated with slip localizations since triple junctions or quadruple points can also produce intragranular orientation gradients that have a similar impact on the grain orientation distribution. Last, comparison with several previously proposed slip transmission criteria indicates that this phenomenon is not relevant, contrary to current belief.

Role of Microstructure on the Development of Local Orientation Gradients in Polycrystals

SSRN Electronic Journal · 2024-01-01

Slip localization behavior at triple junctions in nickel-base superalloys

Acta Materialia · 2023-02-25 · 37 citations

Integrating in-situ multi-modal characterizations with signatures to investigate localized deformation

Materials Characterization · 2023-09-20 · 4 citations

Bringing to Life a Newly Discovered Signature of Fatigue Crack Initiation via Multimodal Characterizations

Research Square · 2022-01-06

Abstract Fatigue is the most prevalent failure mode in structural materials, yet remains challenging to study due to the seemingly unpredictable nature of crack initiation. To elucidate the driving forces of crack initiation in ductile polycrystalline metals, we employ a multimodal approach to identify and track grains with a suspected potential to initiate fatigue cracks via a newly founded signature. We discover this crack initiation potential (CIP) signature under the hypothesis that slip localization, a well-known precursor to crack initiation, is linked to intragrain misorientation, which can be quantified through single grain orientation distributions. We verify the CIP signature in an Inconel-718 material via static two-dimensional and three-dimensional electron microscopy and “bring to life” the dynamics of the CIP signature via in-situ synchrotron X-ray diffraction. With this CIP signature, we move to better focus studies of fatigue crack initiation on the individual grains and processes that drive fatigue failure.

Multi-modal Dataset of a Polycrystalline Metallic Material: 3D Microstructure and Deformation Fields

Scientific Data · 2022-08-01 · 34 citations

The development of high-fidelity mechanical property prediction models for the design of polycrystalline materials relies on large volumes of microstructural feature data. Concurrently, at these same scales, the deformation fields that develop during mechanical loading can be highly heterogeneous. Spatially correlated measurements of 3D microstructure and the ensuing deformation fields at the micro-scale would provide highly valuable insight into the relationship between microstructure and macroscopic mechanical response. They would also provide direct validation for numerical simulations that can guide and speed up the design of new materials and microstructures. However, to date, such data have been rare. Here, a one-of-a-kind, multi-modal dataset is presented that combines recent state-of-the-art experimental developments in 3D tomography and high-resolution deformation field measurements.